This page presents some ideas for expressing NDVI in terms of population density for the City of Denver, Colorado.
A map of population density by block group per 2016-2020 American Community Survey 5-year Estimates
Population density tertiles
A map of NDVI of each block group. Note NDVI is measured using Landsat-8 at a spatial resolution of 30 meters squared on July 4, 2021, a cloud-free day. The weighted average NDVI of each block group excludes bodies of water.
NDVI tertiles, overall




The first is difficult to visualize on a map because the distribution has a right skew with some very high values and most much lower.
## Min. 1st Qu. Median Mean 3rd Qu. Max. NA's
## 457.5 14482.2 22057.3 35548.7 36465.0 364573.0 8

The second is easier to visualize because the distribution is uniform by definition (a simple rank).
## Min. 1st Qu. Median Mean 3rd Qu. Max. NA's
## 1.0 131.5 262.0 262.0 392.5 523.0 8

Map population density per NDVI and the ranking of population density per NDVI on the same map.
Ratio of block group NDVI compared with the median NDVI of the highest NDVI tertile in that population density tertile
Difference of block group NDVI compared with the median NDVI of the highest NDVI tertile in that population density tertile
Copyright © 2022 Michael D. Garber